[llvm-tblgen] Fix parser error when using generic used as index

[GuillaumeGomez]

Summary

Using a generic variable as list index was throwing an error

[GuillaumeGomez]

To provide more context: I use this tool to generate the intrinsics list for the rustc_codegen_gcc project to automatically generate the list of intrinsics used by LLVM so they can be translated to GCC's. Currently, when running it, it fails because of this error:

llvm/IR/Intrinsics.td:225:21: error: Variable not defined: 'al'
  int num = Mapping[al];
                    ^
llvm/IR/Intrinsics.td:225:23: error: expected integer or bitrange
  int num = Mapping[al];
                      ^
llvm/IR/Intrinsics.td:225:23: error: expected ';' after declaration
  int num = Mapping[al];
                      ^

This patch fixes this bug.

[GuillaumeGomez]

CI passed.

[chapuni]

@GuillaumeGomez Thanks for catching this. Seems reasonable to me.

I think the test may be put into ListSlices.td.

Excuse me, let me delegate the acceptance.

[arsenm]

llvm/test/TableGen/var-index.td

2

Can you add checks for the expanded output?

[GuillaumeGomez]

llvm/test/TableGen/var-index.td

2

Sorry but what is the option for doing that? The only two for expansion I see are --print-sets and --instr-info-expand-mi-operand-info and they don't seem to match what you expect.

[hliao]

I don't see this issue from the main branch. In fact, https://reviews.llvm.org/D149016 solves the issue and should not be "fixed". Could you double-check whether the main branch could reproduce this issue?

Add @pcwang-thead

[GuillaumeGomez]

Just confirmed locally with latest main that the issue is solved. Thanks!

llvm/lib/TableGen/TGParser.cpp

return Name->getValue() == "NAME"
                ? VarInit::get(ArgName, StringRecTy::get(Records))
                : nullptr;
   };
 
   // If not found, we try to find the variable in additional variables like
   // arguments, loop iterator, etc.
   switch (Kind) {
   case SK_Local:
-    break; /* do nothing. */
   case SK_Record: {
     if (CurRec) {
       // The variable is a record field?
       if (RecordVal *RV = CurRec->getValue(Name)) {
         if (TrackReferenceLocs)
           RV->addReferenceLoc(NameLoc);
         return VarInit::get(Name, RV->getType());
       }

llvm/test/TableGen/var-index.td

+// RUN: llvm-tblgen %s
+
+class ResolveArgCode<
+    list<int> Mapping,
+    int ax> {
+  int al = !and(ax, 0x00FF);
+  int num = Mapping[al];
+}
+
+def foo : ResolveArgCode<[0, 1], 0>;